This invention relates to a shearing tool for synthetic resin tubes such as hard vinyl chloride tubes and hard vinyl conduit tubes.
Synthetic resin tubes were hithertofore sheared by a saw, but such shearing operation by the saw required rather long time and much labor and the cut faces produced in the sheared tubes were unsatisfactory to the degree that the cut faces required trimming or elaborate finish and thus, the shearing of synthetic tubes by saws were inefficient. Furthermore, although various shearing tools in the form of scissors for synthetic resin tubes have been proposed and practically employed, such prior art shearing tools have the following inherent disadvantages:
1. During the shearing operation, the tube can not be supported in a stablized state and therefore, the shearing operation is difficult and can not produce a satisfactory or exact cut face and as a result, it requires an additional step for trimming or finishing the cut face.
2. Since a great deal of manual effort or gripping force is required, a powerful and sufficient shearing force can not be obtained.
3. Since a tube is not suitably supported, the tube tends to easily crack and/or break.
4. A positive and precise shearing action can not be obtained easily and requires a skilled hand for the purpose.
5. The tube can not be sheared with a constant manual effort or gripping force from the beginning to the completion of the shearing operation and as a result, a smooth shearing operation can not be easily performed.
6. Production cost is high and the shearing operation is expensive.